Carbon paper



5 9 1933 H. w. A. DIXON 1,925,235

cmaori PAPER Filed Jan. 24, 1931 INVENTOR Patented Sept. 5, 1933 UNITEDSTATES PATENT OFFICE Application January 24, 1931. Serial No. 510,945

3 Claims. (01. 282-28) My invention relates to copying processes andparticularly to papers used for making the master copy employed in whatis known as the hectograph process, and for other purposes.

One object of my invention is to provide a copying paper, commonlycalled a hectograph carbon paper, which will produce a stronger mastercopy for the hectograph process. Other objects and advantages of theinvention will be set forth in part hereinafter 'and in part will beobvious herefrom, or may be learned by practice with the invention, thesame being realized and attained by means of the instrumentalities andcombinations pointed out in the appended claims.

In the hectograph process the words, figures or designs to be reproducedare first prepared on a sheet of paper or other suitable surface,

by typewriting, printing, writing, drawing or the 7 like. In doing so aparticular kind of ink is used, known as hectograph ink. This ink may beon the typewriter ribbon used in the typewriter employed to prepare themaster copy, or it may be used with an ordinary writing pen, or it maybe in the coating of a carbon paper used in a typewriting machine.

In the practice of the hectograph process a master copy is prepared byany of the above enumerated methods, using an ink having certaincharacteristics, including a very penetrating quality, and also apowerful dyeing quality. Such ink is composed largely of aniline dyewith a menstruum as a carrying vehicle. The men: struum consists of,oils and waxes. After the master copy is prepared, it is laid face downand pressed into intimate contact with a sheet or layer of a suitablecolloidal material, such for example, as gelatin, and allowed to remainfor a short period of time, rarely over one minute. During this periodthe highly penetrating ink penetrates into the colloidal material,leaving the surface of the master copy and going to the colloid, whichhas a strong affinity for the aniline dye of the ink and absorbs itquickly. The in tensity of the impregnation of the colloid by the ink isproportional to the intensity of the ink on the master copy. The mastercopy is next removed from the surface of the colloid and the desiredduplicate copies of the master copy are made by laying sheets of paper,one after another, on the surface of and in intimate contact with thecolloid. Each sheet of paper so pressed against the surface of thecolloid receives ink from the surface of the colloid and after each suchimpression the ink on the surface is slightly diminished, so that ascopy after copy is taken readily legible.

off the copies become less bright and distinct until they finally becomeso faint as not to be The number of legible copies which may be madefrom a master copy is dependent upon or is influenced by a number offactors, chief among which is the intensity of the ink on the mastercopy. When the master copy is printed the-intensity of the ink islargely governed by the amount of ink laid on the type by the rollers ofthe printing press at the time of printing. When the master copy is madein a typewriter using ribbon impregnated with hectograph ink, theintensity of the ink on the master copy is largely dependent on theamount of ink in the ribbon and the newness or age of the ribbon. Whenthe master copy is prepared by using a carbon paper coated withhectograph ink, the intensity of the ink on the master copy is dependentlargely on the coating on the paper and the amount of 5 the coatingwhich is transferred from the carbon paper to the master copy whenstruck by the type bar of the typewriter. When the paper used in makingthe carbon paper is of an absorptive nature, a considerable portion ofthe coating of hectograph ink penetrates into the paper at the time ofcoating, and is not readily transferred from the carbon paper to themaster copy when struck by the type bar of the typewriter.

My invention relates particularly to this feature of the copy paper.Heretofore papers used in the manufacture of carbon paper for thispurpose have been of the absorptive type, and a considerable portion ofthe ink coating applied to the surface of such paper in the process ofmanufacture has been absorbed into the fibres of the paper and so cannot be transferred to the master copy by the pressure.

It has been common practice in the manufacture of carbon papers to usepaper made from fibrous materials of high absorption, such for example,as flax, all of a costly type and having long fibres. I have discoveredthat the qualities heretofore sought and strived for by the manufacturesdo not produce in the highest degree the results desired from a carbonpaper for use in making master copies for hectographing. When makingsuch master copies the object is to transfer as much as possible of theink from the carbon paper to the master copy at the time of writing. Thedesired end would be obtained if all of the ink on the carbon paper inthe area struck by the type bar were transferred from the carbon paperto the master copy.

By using a non-absorptive paper having a glazed surface, to which theapplied coating of ink will adhere, but into which it can not penetrate,I produce a carbon paper from which the hectograph ink is almostcompletely transferred to the master copy when pressure is applied, as

for example, when struck by the type bar of a typewriter or otherwisepressed into firm contact with the master copy. I find that by using atreated paper of a type which is highly impervious and impenetrable, Iam able to apply thereto a coating of hectograph ink, which will give amuch denser layer of ink on the master copy than is possible whenabsorbent paper is used to receive the coating of This is because mynon-absorbent paper permits practically all of its coating of ink to bedetached from the surface of the copy paper and be transferred to thesurface of the master copy by the pressure of the type bar. Almost acomplete transfer takes place, for the reason that practically none ofthe coating of ink on the impervious copy paper has been absorbed intothe paper, but practically all the ink is still on the surface and isreadily detached therefrom and wholly transferred to the master copyunder the influence of pressure. As an example of the type of paperwhich I find suitable for this service, I may mention the kind commonlyknown in the trade as glassine paper.

Many other papers possess the requisite nonabsorbing quality besidesglassine paper. Any thin, uniform paper, to which the ink will adhere,but into the body of which the ink will not penetrate, and having theusual other qualities necessary-in a carbon paper, such as freedom fromimperfections, etc., may be used. Suitable papers may be prepared byapplying impenetrable coatings to otherwise penetrable paper, or bysaturating the body:I of the paper with a suitable penetration resistanmaterial to render the paper resistant to the bsorption of thehectograph ink. Nor do I limit my base membrane on which I app y y inkcoating to paper alone, since I may also use various membranes, such ascelluloid, cellophane, rubber, fabrics or any other sufficient- 1y mm,uniform and" impervious membrane.

Intheaccompanying drawing Fig. l is a much enlarged cross section of aportion of carbon paper made according to my invention, in which 1 isthe coating of hectograph ink and 2 is the base of impervious membraneto which the ink is applied. By the practice bf my invention I am ableto place a much denser layer of ink on the master copy, which in turnresults in a much denser impregnation of ink intothe surface of thecolloid when the master copy is brought into contact therewith, and as aresult a much greater number of legible copies may be taken from thesurface of the colloid. I find that by the practice of my invention I amable to make some 50% more legible copies of a typewritten master copythan with the best copy paper of the absorptive type heretofore on themarket.

In making my new carbon paper, I use for convenience paper known in thetrade as glassine paper of various thicknesses, from the thin variety,half a thousandth of an inch thick, up to the heavy varieties, measuringas much as two thousandths of an inch in thickness. I coat this paperwith an ink composed of a mixture of oils and waxes, into which isground a very large proportion of aniline dyes of various types andcolors, such as crystal violet or methylene blue, and others, dependingon the color desired and the purpose for which it is to be used.

The term carbon ink is used in the trade and in this description, and inthe following claims, to mean any ink of any color or formula which isused in the manufacture of carbon paper.

The term carbon paper is used in the trade and in this description andin the following claims to mean any ink coated paper which will ing ofink on a membrane which it can not pene-- trate, but from which it ispractically all removed by pressure against a receiving surface, is tobe preferred to a heavier coating of ink on the usual type of basemembrane. i

Another application of my invention is in making of copies of writingsor drawings by photographic means. In this application the carbon paperis used as a negative to print copies of the original writing. When mynew carbon paper is used in the ordinary manner, the ink coating is sonearly completely removed from the surface area affected by the pressureapplied that a transparent or translucent area is left. Such a sheet ofcarbon paper, after having received the desired writing or drawing, 'maybe used to produce as many duplicates as may be desired by well-knownphotographic means.

Having described my invention and the manner of its use, I new statewhat I claim to be new and for which I pray that Letters Patent begranted. a

l. A carbon paper consisting in combination of glassine'paper base towhich has been applied a coatingof hectograph ink.

2. A carbon paper consisting of glassine paper base to which has beenapplied an ink coating.

3. A carbon paper consisting of cellophane having a coating of ink.

. HAROLD W. A. DIXON.

For. example, carbon papers areused in certain cases where only onewriting is

